Water intoxication, which results in life threatening hyponatremia (excessively low sodium levels), is a relatively rare but frequently fatal condition in dogs. At highest risk are dogs that enjoying playing in the water for long stretches. But believe it or not, even a lawn sprinkler or hose can pose a hazard for pets that love to snap at or “catch” spraying water.
What Happens When a Dog Ingests Too Much Water

Hyponatremia occurs when more water enters the body than it can process. The presence of so much water dilutes bodily fluids, creating a potentially dangerous shift in electrolyte balance. The excess water depletes sodium levels in extracellular fluid (fluid outside of cells). Sodium maintains blood pressure and nerve and muscle function.
When the sodium concentration in extracellular fluid drops, the cells start filling with water as the body attempts to balance the sodium levels inside the cells with falling levels outside the cells. This inflow of water causes the cells – including those in the brain – to swell. The central nervous system can also be affected.
Symptoms of water intoxication include staggering/loss of coordination, lethargy, nausea, bloating, vomiting, dilated pupils, glazed eyes, light gum color, and excessive salivation. In severe cases, there can also be difficulty breathing, collapse, loss of consciousness, seizures, coma, and death.
Dogs Most at Risk for Water Intoxication

Any dog can develop hyponatremia, however, the condition is most commonly seen in dogs who will stay in the lake, pond or pool all day if you let them; pets that lap or bite at the water continuously while playing in it; and dogs that swallow water unintentionally as they dive for a ball or other toy.
The condition has also been reported in dogs that over-hydrate during or after exercise, as well as those that enjoy playing with water from a garden hose or sprinklers.
Water intoxication can affect any size or breed of dog, but smaller dogs probably show symptoms more quickly because it takes less time for an excessive amount of water to build up in their bodies.
Water intoxication progresses quickly and can be life threatening, so if your pet has been playing in water and begins to exhibit any of the symptoms listed above, it’s crucial that you seek immediate veterinary care to save your dog’s life.
Treatment of hyponatremia in dogs typically includes IV delivery of electrolytes, diuretics, and drugs to reduce brain swelling. With aggressive veterinary care, some dogs are able to recover from water intoxication, but sadly, many are not.
Preventing Water Intoxication in Your Dog



If your dog loves the water, make sure you’re there to supervise his activity. If your pet is repetitively retrieving a ball or other toy from the water, insist on frequent rest breaks. Be especially vigilant on days when the water is rough.
Observe how your dog interacts with the water. If her mouth is open a lot – even if she’s holding a ball or stick in it -- understand that she’s likely ingesting a fair amount of water. The same can be true of dogs that dive to the bottom of a pool to retrieve items.
Familiarize yourself with the symptoms of water intoxication and monitor your dog’s appearance and behavior when she’s playing in water.
After a period of hard play or exercise, use caution when your dog rehydrates. If he immediately laps up the contents of his water bowl, rest him for a bit before you refill his bowl. If your dog is very active, it’s a good idea to have water with you when he exercises so that you can give him frequent short water breaks to keep him hydrated.
If your dog enjoys interacting with water from the hose or sprinkler, you should monitor that activity as well. Water from a hose or sprinkler is under pressure, and you’d be surprised how much a dog can ingest in a short amount of time.
A Word About Salt Water Toxicity

Excessive intake of salt water can result in hypernatremia, or salt poisoning, which is the opposite of hyponatremia. Initial signs of hypernatremia include vomiting and diarrhea, but the condition can quickly progress to neurologic symptoms like loss of coordination, seizures, progressive depression, and severe brain swelling.
Hypernatremia, like hyponatremia, is potentially life threatening, and immediate veterinary care is needed.
If you take your dog to the beach, bring along fresh drinking water and offer it to him at frequent intervals so he won’t be tempted to drink ocean water.

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